https://ecode360.com/15245641#15245642 seems like condo conversions is not permitted in Hoboken but curious what's the result of your case. 

I'm a contractor and just did a bid on an SB9 project in Los Angeles County - Altadena area (building permit jurisdiction).

I like both of your ideas so I would look for the single where an ADU is permitted or one with a dump ADU to renovate (that's best) and balance that against the purchase of a 2-4 unit.

As an example, we decided to replace the windows in a house we were renovating and ended up costing us $50,000 extra because we got into issues with permitting and suddenly found ourselves having to hire an architect, speciality contractors, etc.  

It was taking 8 weeks for septic permits and 4 months for surveys. 

The owner can designate a host who shall be responsible, and authorized, to act on the owner's behalf to promptly remedy any violation of these standards or the permit.

Applications were being lost, or the website wasn't permitting tenants to fill them out.

There are a few different avenues that my clients have been exploring, including getting unpermitted units actually permitted.

Duplex have different zoning that may permit additional units.

If it helps, I've inserted a link to Cape Coral's permitting site below where you can check the status of work progress and inspections.